The invention relates to a seal for a control device of a supercharger, in particular for an exhaust gas turbocharger with a valve means in the form of a waste gate, with a bearing element supporting a control shaft.
Control devices of this type are well known. DE 20 2005 008 606 U1 discloses for example a control shaft arrangement of a turbocharger with a variable turbine geometry or with a waste gate, respectively, which includes a control shaft provided with a mounting section. The control shaft arrangement also includes a lever which is connected to the control shaft via the mounting section, and a bushing which is arranged on a base body of the control shaft. In addition, a seal is provided which is arranged in the area of the base body between the bushing and the control shaft, with the base body of the control shaft having a stepped outer contour and the bushing having an inner contour which is formed complementarily to the shape of the base body.
Sealing of the control shaft arrangement by means of the seal which is positioned between the control shaft and the bushing has the drawback that the control shaft comprises a groove which corresponds to the seal and which results in a weakening of the control shaft. This presents a problem insofar as the control shaft is subjected to high temperatures, which leads to an increased failure probability of the shaft and the control device because the shaft is weakened by the groove. Moreover, the installation of the seal is extremely laborious and therefore involves high expenditures with respect to time and cost.
Another problem may occur by the fact that the bushing needs to be sealed with respect to a housing which accommodates the bushing, and which may cause undesired gas leakage.
It is therefore the principal object of the present invention to provide a seal for a control device of a supercharger in an exhaust gas turbocharger with a valve means in the form of a waste gate, which provides for improved and simple sealing.